Semiconductor laser output control device

摘要

A semiconductor laser output intensity control device is provided in a laser beam scanning system, such as a laser printer. A laser beam emitted from a semiconductor laser is modulated by image information and scanned across a photosensitive member for forming an image thereon. The present output intensity control device employs an up/down counter whose count determines the level of driving current to be applied to a laser driver which drives the semiconductor laser. The up/down counter changes its count either up or down depending on the magnitude of the output intensity of the laser beam as compared with a reference level. The present device includes a control circuit which prevents the power setting operation of the laser from taking place during a scanning time period in which the photosensitive member is scanned by the laser beam.